Inkjet printers print images onto media by ejecting ink drops from a printhead. Each printhead typically has an array of nozzles that eject the ink drops onto the media. When a nozzle is plugged or incorrectly ejects the ink drops to a different position on the media, the image quality of the printed output may degrade. With the increase in the number of nozzles per printhead, detecting improperly functioning nozzles has become more difficult.